Biodiversity of insect pest complex infesting okra [Abelmoschus esculentus] in Tripura, N.E. India

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1 2017; 5(5): E-ISSN: P-ISSN: JEZS 2017; 5(5): JEZS Received: Accepted: Navendu Nair Department of Agriculture Agriculture, Tripura, U Giri Department of Agronomy, T Bhattacharjee Department of Horticulture, B Thangjam Department of Agriculture Agriculture, Tripura, N Paul Department of Soil Science, MR Debnath Horticulture Research Centre, Nagicherra, Tripura, Biodiversity of insect pest complex infesting okra [Abelmoschus esculentus] in Tripura, N.E. Navendu Nair, U Giri, T Bhattacharjee, B Thangjam, N Paul and MR Debnath Abstract Field experiments were conducted to study the biodiversity of insect pest infesting okra in Tripura during two seasons viz, summer (April to July, 2016) and winter (October, 2016 to January, 2017). A total of twenty eight insect pest belonging to 6 orders were found to infest this crop. Maximum number of were belonging to Hemiptera (12 nos.) followed by Lepidoptera (9 nos.) and Coleoptera (4 nos.). The Shannon and Wiener diversity index (H ) during summer and winter season for the insect pest complex of okra was calculated as 1.01 and 0.91, respectively. The Simpson s diversity index (D) during summer and winter season was calculated as 0.14 and 0.19, respectively. These two indices for summer and winter season were more or less equal and exhibited a similar diversification. Similarly, Species Richness (7.31 and 7.49) and Species Evenness (0.71 and 0.64) during summer and winter season were more or less equal. However, by number the Leaf hopper (Amrasca biguttula biguttula ), Leaf beetle (Podagrica sp.), Blister beetle (Mylabris pustulata) and Leaf folder (Syllepte derogata) were more abundant in the field during summer season where as, Leaf hopper (Amrasca biguttula biguttula), Aphid (Aphis gossypii), White fly (Bemisia tabaci) and Leaf folder (Syllepte derogata) were more abundant during winter season. However, during Summer season Blister beetle (Mylabris pustulata), Leaf beetle (Podagrica sp.) and Red cotton bug (Dysdercus cingulatus) were found to be major pests causing considerable damage whereas, during winter season Shoot and fruit borer (Earias vittella) was found to be the major pest. Keywords: Okra, pest complex, biodiversity, Tripura, North East 1. Introduction Okra (Abelmoschus esculentus L. Moench, Family- Malvaceae), commonly known as Bhindi or Ladies finger is one of the most popular and commercially cultivated vegetable crops in. It is mainly cultivated to produce the fruits that are consumed as a vegetable in a variety of ways. Okra is a rich source of carbohydrate, protein, fats, vitamins and minerals [1]. It is one of the major vegetable crops being widely grown throughout the year by the farmers of Tripura. Incidences of many insect pests on okra have been reported by many workers from different parts of the Country and some of which are responsible for considerable yield loss [7, 9, 11, 17]. However, insects, occupying vital positions in food webs, play an important role in maintaining ecological balance. Moreover, the diversity of insects and their pest status varies from region to region with the variation in agro climatic conditions. Before an intelligent decision can be made about management of the insect pests, it is necessary to be able to properly identify which of insects are major pests. Information on the occurrence of pests of okra in Tripura is lacking. So the present work was carried out to study the biodiversity of insect pest complex infesting Okra in this state. 2. Materials and Methods The experiment was conducted in the experimental farm of College of Agriculture, Lembucherra, Tripura during two seasons viz., summer season (April to July, 2016) and winter season (October, 2016 to January, 2017). Correspondence Navendu Nair Department of Agril. Agriculture, Tripura, 2.1 Crop studied: The seeds of the okra variety NS 810 were sown in the 1st week of April for the summer crop and in the 1 st week of October for the winter crop. The crop was grown following all standard agronomic practices excepting plant protection measures. ~ 1968 ~

2 2.2 Method of observation: Insect pests occurring on Okra plants were observed at weekly intervals from 20 randomly selected plants from seedling stage to maturity of the crop through Plant Inspection Method (PIM). H = Shannon - Wiener index S = Number of in the community Species richness 2.3 Grouping of insect pests: Recorded insect were categorized as major and minor pests on the basis of their incidence pattern. Insects which infested the crop in considerable numbers and were responsible for considerable damage with prominent damage symptoms like severe defoliation, growth retardation or damage to economic plant parts i.e. flowers and fruits (more than 5% damage) were considered as major pests. Insects which were encountered in a small number or which did not produce any prominent damage symptom or did not cause any substantial damage (less than 5%) were designated as minor pests. 2.4 Statistical analysis Measurement of Relative abundance: To measure the percentage of individuals of a particular over all the following formula was used: R A= Relative abundance Measurement of Biodiversity indices Biological diversity studies use diversity indices as indicators. Following formulae were used to calculate the diversity indices. Simpson index D = Simpson index Shannon - Wiener index H = Shannon - Wiener index Species evenness J = evenness R = Species richness S = Number of in the community 3. Results and Discussion Insect pest recorded in Okra crop during present study are presented in Table 1. A total of 28 insect pests belonging to 6 orders and 20 families were recorded. Among these, the maximum number of were belonging to Order Hemiptera (12 under 10 families) followed by Lepidoptera (9 under 4 families) and Coleoptera (4 under 3 families). Remaining three orders namely, Diptera, Orthoptera and Thysanoptera were represented by one each. Relative abundance of insect pests belonging to different orders is shown in Fig.1. During summer, 2016 a total of 3613 individuals belonging to 27 under 6 orders were collected from 240 randomly selected plants during 12 weeks of crop period. By number the Leaf hopper (Amrasca biguttula biguttula), leaf beetle (Podagrica sp.), blister beetle (Mylabris pustulata) and Leaf folder (Syllepte derogata) were more abundant in the field during the summer season with 23.64%, 19.13%, 15.50% and 8.86% relative abundance, respectively. However, during this season Blister beetle (Mylabris pustulata), Leaf beetle (Podagrica sp.) and Red cotton bug (Dysdercus cingulatus) were found to be major pests causing considerable damage. Adults of blister beetle were recorded to voraciously feed on flower buds and flowers hampering fruit setting. Both adults and nymphs of red cotton bug were found to infest the leaves, shoots and fruits and as a result of their feeding of sap the fruits were deformed with the development of some characteristic markings on the same making it unmarketable. Adults of Leaf beetle (Podagrica sp.) were recorded to appear in large number feeding on leaves making numerous holes on the infested leaves leading to reduced photosynthesis activity and growth retardation of the plants. Earlier, Flea beetle, Podogrica bowringi Baly was reported as the major pest on okra in Uttarkashi district of Uttaranchal [12]. Leaf beetle and blister beetle were reported as some of the key pests of okra causing significant crop damage at Kalimpong, West Bengal [14]. Blister beetle and Red cotton bug were reported as major pest out of 11 insects and 1 mite pest infesting okra in Mizoram [3]. Major pest status of insect pests as recorded in these two studies [14, 3] in April sown a crop of okra are in agreement with the present findings. Blister beetle, red cotton bug and Shoot and fruit borer have earlier been reported to be some of the major pests of Okra [7, 17]. Earlier, Chakraborty et al. [5] and Pal and Satpathi [14] also studied the biodiversity of insects in okra ecosystem in Karaikal, U. T. of Puducherry and Kalimpong, West Bengal, respectively. Both of these studies recorded Hemipteran herbivores as the most abundant and diverse insect group in okra ecosystem which is in agreement with the present study. However, Lepidoptera was recorded as the second most diverse insect group during the present study which does not corroborate with the earlier two works as both of these recorded Coleoptera as the second most diverse group. ~ 1969 ~

During winter, 2016-17 a total of 2955 individuals belonging to 27 insect under 6 orders were collected from 240 randomly selected plants during 12 months of crop period.

3 During winter, a total of 2955 individuals belonging to 27 insect under 6 orders were collected from 240 randomly selected plants during 12 months of crop period. By number, Leaf hopper (Amrasca biguttula biguttula), Aphid (Aphis gossypii), White fly (Bemisia tabaci) and Leaf folder (Syllepte derogata) were more abundant during this season with 36.72%, 14.25%, 13.71% and 8.46% relative abundance, respectively. According to Anitha and Nandihalli [2] the sucking pests viz., aphid (Aphis gossypii) leafhopper (Amrasca biguttula biguttula), whitefly (Bemisia tabaci) and mite (Tetranychus sp.) are of regular occurrence and cause considerable damage in okra. However, during this season of present study, only one pest i.e. Shoot and fruit borer (Earias vittella) was recorded as major pest. The larvae bored the tender shoot during the vegetative stage of the crop resulting in drooping and drying of infested shoots hampering growth of the plants. During the reproductive stage of the crop the larvae bored into the fruits feeding on inner contents making them deformed in shape and unfit for consumption. This finding is in agreement with Gautam et al. [10]. Earlier, many studies have recorded this pest as one of the major pest infesting okra causing considerable yield loss [6-8, 15, 16]. However, its occurrence was not recorded in April sown crop during the present study and this is in conformity with Pal and Satpathi [14] and Boopathi, et al. [3] who also could not record Earias vittella in April sown okra crop in North Eastern hilly areas of. Though whitefly, aphid and leaf hopper were relatively abundant in one or both the seasons but their population level was not sufficient to produce any prominent damage symptoms and hence they were considered as of minor significance. All other insect pests recorded were of minor significance. Dhamdhere et al. [7] reported 13 insect and non-insect pests attacking okra at various stages of crop growth, the major being A. biguttula biguttula, B. tabaci, S. derogata, Mylabris spp., D. koenigii and E. vittella. Among the insect pests recorded infesting okra during the present study, Bemisia tabaci, Aphis gossypii, Phenacoccus solenopsis, Nezara viridula, Ricania speculum, Leptocentrus taurus, Cletus punctiger, Helicoverpa armigera and Mylabris pustulata have earlier been reported to infest Pigeon pea in Tripura [13]. The Shannon and Wiener diversity index (H ) during summer and winter season for the insect pest complex of okra was calculated as 1.01 and 0.91, respectively indicating almost similar diversification during the two seasons. The Simpson s diversity index (D) during summer and winter season was calculated as 0.14 and 0.19, respectively which were more or less equal and indicate a high degree of diversity among insect pest in Okra ecosystem during both the seasons. Similarly, Species Richness (7.31 and 7.49) and Species Evenness (0.71 and 0.64) during summer and winter season were more or less equal. 4. Conclusion It is, therefore, evident from the present study that a considerably large number of insect pest infest Okra crop grown in this state and estimated values of biodiversity indices during two different seasons viz., summer and winter were more or less equal. However, seasonal variations in relative abundance as well as pest status of the insect are observed. It is also evident from this study that mere occurrence of pest with comparatively higher percent of relative abundance is not sufficient for the pest to be considered as major one. Rather, some with relatively lower population frequency may appear with major pest status depending on the nature of damage and plant parts they infest as in case of Leaf beetle, Blister beetle, Red cotton bug and Shoot and fruit borer which need primary focus for formulating effective pest management strategy. 5. Acknowledgments The authors are very grateful to the Principal, College of Agriculture, Tripura for the liberal facilities provided for this study. The authors are also very grateful to Zoological Survey of, Kolkata for identification of some of the supplied insect specimens. Fig 1: Relative abundance of insect pests belonging to different orders. Table 2: Diversity, evenness and richness of insect pest complex in Okra during two seasons: Season No. of Species Total no. of Shannon-Wiener Simpson s Species Species individuals index Index Evenness Richness Summer, Winter, ~ 1970 ~

4 Table 1: Insect pest complex associated with Okra in Tripura: Sl. No. Order and Family Common name Scientific name Plant parts infested Relative abundance Summer, 2016 Winter, Summer, 2016 Pest status Winter, A Hemiptera 1 Cicadellidae Okra leafhopper Amrasca biguttula biguttula (Ishida) Leaf Minor Minor 2 Cicadellidae Sharpshooter Bothrogonia leafhoppers albidicans (Walker) Leaf Minor Minor 3 Aleyrodidae White fly Bemisia tabaci (Gennadius) Leaf Minor Minor 4 Aphididae Cotton aphid Aphis gossypii (Glover) Leaf, Flower buds, Flowers Minor Minor 5 Pyrrhocoridae Red Cotton Bug 6 Pseudococcidae Cotton mealybug Dysdercus cingulatus Phenacoccus solenopsis (Tinsley) 7 Pentatomidae Green stink bug Nezara viridula (Linnaeus) Leaf, shoot and Fruit Major Minor Leaf, fruit Minor Minor Leaf, shoot and fruit 8 Pentatomidae Shield bug Menida histrio Buds, fruits Minor Minor Ricaniidae Black leafhopper Ricania speculum (Walker) Leaf, stem Minor Minor 10 Membracidae Cow bug Leptocentrus taurus Leaf, stem Minor Minor 11 Coreidae Coreid bud Cletus punctiger (Dallas) Leaf Minor Minor 12 Rhopalidae Scentless plant bug Liorhyssus rubicundus (Signoret) Leaves and buds Minor Minor Minor Minor B Lepidoptera 13 Noctuidae Cotton semilooper Anomis flava Leaf Minor Minor 14 Noctuidae Semilooper Anomis fulvida (Guenee) Leaf Minor Minor 15 Noctuidae American boll worm Helicoverpa armigera (Hübner) Fruit Minor Minor 16 Noctuidae Tobacco caterpillar Spodoptera litura Leaf Minor Minor 17 Nolidae Cream drab Xanthodes albago Leaf Minor Minor 18 Nolidae Transverse moth Xanthodes transversa (Guenee) Leaf Minor Minor 19 Nolidae Shoot and fruit borer Earias vittella Shoot, fruit Major 20 Crambidae Cotton leaf roller Syllepte derogata Leaf Minor Minor 21 Arctiidae Bihar hairy caterpillar Spilosoma obliqua (Walker) Leaf Minor Minor C Coleoptera 22 Chrysomelidae White-spotted leaf Monolepta Leaf, flower beetle signata (Olivier) Minor Minor 23 Chrysomelidae Leaf eating beetle Podagrica sp. Leaf Major Minor 24 Curculionidae Ash weevil Myllocerus discolor (Boheman) Leaf Minor Minor 25 Meloidae Blister beetle Mylabris pustulata (Thunberg) Flower buds and Flower Major - D Diptera 26 Agromyzidae Serpentine leafminer Liriomyza trifolii (Burgess) Leaf Minor Minor E Orthoptera 27 Pyrgomorphidae Tobacco grasshopper Atractomorpha crenulata Leaf Minor Minor F Thysanoptera 28 Thripidae Onion thrips Thrips tabaci (Linderman) Leaf Minor Minor ~ 1971 ~

Fig 2: Insect pests of okra: 1. Xanthodes transversa, 2. Syllepte derogata, 3. Anomis fulvida, 4. Helicoverpa armigera, 5. Earias vittella, 6. Spilosoma obliqua, 7. Nezara viridula, 8.

5 Fig 2: Insect pests of okra: 1. Xanthodes transversa, 2. Syllepte derogata, 3. Anomis fulvida, 4. Helicoverpa armigera, 5. Earias vittella, 6. Spilosoma obliqua, 7. Nezara viridula, 8. Myllocerus discolor, 9. Ricania speculum, 10. Mylabris pustulata, 11. Cletus punctiger, 12. Monolepta signata, 13. Dysdercus cingulatus, 14. Aphis gossypii, 15. Amrasca biguttula biguttula 10. Gautam HK, Singh NN, Rai AB. Screening of okra against shoot and fruit bores Earias vittella (Fab.). n Journal of Agricultural Research. 2014; 48(1): Kumar U, Singh DV, Sachan SK, Bhatnagar A, Singh R. Insect pest complex of okra and biology of shoot and fruit borer, Earias vittella (F.). n Journal of Entomology. 2014; 76(1): Lal OP. An unusual high incidence of the flea beetle, Podogrica bowringi Baly (Coleoptera: Chyrsomelidae) on okra in Uttarkashi district of Bhagirathi valley in central Himalaya (). Journal of Entomological Research. 1999; 23(1): Nair N, Shah SK, Thangjam B, Debnath MR, Das P, Dey B et al. Insect pest complex of Pigeon pea (Cajanus cajan) in agro ecosystem of Tripura, N.E.. Journal of Entomology and Zoology Studies. 2017; 5(4): Pal S, Satpathi SK. Species Richness and Relative Abundance of Pest Faunal Complex Infesting Okra under Mid-Hill Conditions of Eastern Himalayas. Journal of Agriculture and Technology. 2016; 3(1): Radke SG, Undirwade. Seasonal abundance and insecticidal control of shoot and fruit borer, Earias spp. on Okra, Abelmoschus esculentus (L.) Moench. n Journal of Entomology. 1981; 43: Rawat RR, Sahu HR. Estimation of losses in growth and yield of okra due to Empoasca devastance Dist and Earias spp. n Journal of Entomology. 1973; 35: Singh R, Joshi AK. Pests of okra (Abelmoschus esculentus Moench) in Paonta Valley, Himachal Pradesh. Insect Environment. 2004, 9(4): References 1. Akintoye HA, Adebayo AG, Aina OO. Growth and yield response of okra intercropped with live mulches. Asian Journal of Agricultural Research. 2011; 5(2): Anitha KR, Nandihalli BS. Seasonal incidence of sucking pests in okra ecosystem. Karnataka Journal of Agricultural Sciences. 2008; 21: Boopathi T, Pathak KA, Ngachan SV, Singh BK, Das N, Verma AK. Seasonal incidence of major insect pests on okra in Mizoram,. The Journal of Plant Protection Sciences. 2011; 3(1): Brar KS, Arora SK, Ghai TR. Losses in fruit yield of okra due to Earias spp. as influenced by dates of sowing and varieties. Journal of Insect Science. 1994; 7(2): Chakraborty A, Kumar K, Chitra N. Computation of insects biodiversity in bhendi (Abelmoschus esculentus (L.) Moench) ecosystem. The Bioscan. 2014; 9(4): Chaudhary HR, Dadheech LN. Incidence of insects attacking okra and the avoidable losses caused by them. Annals of Arid Zone. 1989; 28(3-4): Dhamdhere SV, Bahadur J, MishraVS. Studies on occurrence and succession of pests of okra at Gwalior. n Journal of Plant Protection. 1984; 12: Dhawan AK, Sindhu AS. Incidence and relative abundance of different of spotted bollworms on okra at Ludhiana, Punjab. Journal of Research Punjab Agriculture Universiry. 1984; 21: Dubey VK, Bhagat KP, Kaushik UK, Yadu YK. Insect pest succession studies on okra. Journal of Applied Zoological Research. 1999; 10(2): ~ 1972 ~

Seasonal incidence of major insect pests of okra in the north eastern hill region of India

Seasonal incidence of major insect pests of okra in the north eastern hill region of India T. BOOPATHI*, K. A. PATHAK, B. K. SINGH and AMITOSH KUMAR VERMA Division of Entomology, ICAR Research Complex